1. Field of the Invention
The present invention relates to a method and apparatus for forming a block of cheese, and more particularly relates to method and apparatus for the collection of sheets of cheese curd and forming the cheese curd sheets into a block.
2. Description of the Prior Art
Over the years, many arrangements have been proposed for the commercial production of cheese and cheese products. One particularly successful arrangement is disclosed in three Letters U.S. Pat. Nos. 3,292,259; 3,353,269; and 3,404,009. As disclosed in these patents, cheese curd is provided in granular form, comprising particles or small aggregations of particles from which substantially all or most of the whey has been drained or otherwise removed. The curd granules are then introduced into a conditioning tower where they are inherently pressed together prior to subsequent hooping at another station. The curd granules are compressed by a weighted plate lowered into the tower. The plate includes a downwardly-projecting ring-shaped member, V-shaped in cross section, which is pressed into the top of the cheese curd granules located at the top of the conditioning tower. While holding the plate in place, the tower is raised so as to eject a pressed curd mass from the bottom of the tower. The curd mass is received in a pan, and forms a generally pyramidal shape. The V-shaped ring facilitates the eve spreading of the curd mass in the pan and aids in maintaining the structural integrity of the upper part of the curd mass, generally preventing disintegration or other deformation thereof. A heated pressure plate applied to the pyramidal curd in the pan flattens the mass to a more uniform depth in the pan to facilitate subsequent operations performed on the curd mass.
In Letters U.S. Pat. Nos. 3,468,026, 4,061,794 and 4,152,101, method and apparatus are disclosed for forming blocks of cheese from cheese curd. Cheese curd is fed into the top of an evacuated perforated column, with vacuum serving to reduce air pockets in the cheese curd. Curd in the lower portion of the column is compressed by the weight of superimposed curd to press out whey therefrom.
In Letters U.S. Pat. No. 3,468,026, the curd may optionally be compressed by forcing the curd into a duct leading to an extrusion nozzle which is blanked off during compression of the curd in the duct. Curd in the tower is lowered by lowering a platform supporting the curd mass. The frictional resistance in the tower, however, was sometimes high enough to cause fractures in the column of cheese curd upon lowering of the curd mass.
In Letters U.S. Pat. Nos. 4,061,794 and 4,152,101, when a sufficient quantity of curd is placed in the chamber, air at elevated pressures is injected in the top of the chamber to consolidate and compress the curd therein, and to press whey from the curd mass through perforations in a liner disposed within the tower. Mention is made in these patents that air is exhausted from the column prior to filling the column with a mixture of cheese curd and salt. However, it is clear that the pressure in the column (whether caused by positive or negative pressures in the column) is controlled so as to prevent forcing the crumbled curd through the perforations of the column wall. The low pressure is sometimes described in the patents as being provided by a "vacuum means", however, the low pressure, even if reduced to sub-atmospheric levels (i.e., a "vacuum") would still have to be of a small magnitude to prevent extruding of curd through the perforate container walls. When curd is ready to be dispelled from the chamber, a guillotine blade supporting the curd mass in the chamber from below is retracted and the curd mass is brought into contact with a movable platform. As the platform is lowered, the curd mass exiting the chamber increases in size. After the desired amount of curd has been extracted from the chamber, the guillotine blade separates the curd mass from the curd remaining in the chamber, above the guillotine blade. The movable platform is thereafter raised to press the block of cheese curd against the underside of the guillotine blade to provide further whey extraction from the block.
Further improvements in the mass production of cheese and cheese products are still being sought to achieve more economical production costs and to avoid the limitations discussed above.
An improved process for the manufacture of cheese is described in co-pending U.S. patent application Ser. No. 649,838, filed Sept. 11, 1984. The invention comprises the production of a sheet of cheese curd which should not be extensively broken up and should retain its sheet form. However, the collection of this sheet of cheese curd in commercial operations has proved to be difficult and is a principal object of the method and apparatus of the present invention.